Fusion systems and methods of assembly and use

ABSTRACT

The present invention discloses fusion systems and methods of assembly and use. The fusion systems include a first fastener, a second fastener, and an elongate member with a first end and a second end. The first end being secured to the first fastener and the second end being secure to the second fastener. The method of assembling a fusion system and methods of using the fusion systems are also disclosed.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority benefit from International ApplicationNo. PCT/US2015/051251 filed on Sep. 21, 2015, which claimed priorityfrom U.S. provisional application No. 62/052,915 filed Sep. 19, 2014,each of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to general surgery, orthopaedicand neurosurgical implants used for insertion within a patient's bones.More specifically, but not exclusively, the present invention concernsfusion and/or fixation systems for implantation into a patient's bonesto maintain or re-establish proper spacing and alignment between orwithin the bones.

BACKGROUND OF THE INVENTION

Spinal deformities may result from disease, age, or trauma causingdestabilization of the spine. To correct destabilization of a patient'sspine, posterior fusion device systems may be used. The posterior fusiondevice systems that are currently available are designed to beapplicable to single and multiple level stabilizations. Currently usedpedicle or polyaxial screws use a top down locking mechanism that mayallow for rod loosening and/or micro motion between the screws due toimproper rod seating which may extend the time to achieve fusion or leadto non-fusion. The rod micro motion may be created by the use of athrough slot in the screw to position the rod and the lack of a physicalconstraint on the end of the rod which is captured within the screw headlocking mechanism. These fusion device systems and the instrumentationused for insertion into a patient's spine are extensive, complicated,and expensive. Further, additional bones in a patient's body may befractured or otherwise damaged from disease, age or trauma and mayrequire systems to maintain or re-establish proper alignment andpositioning. Therefore, improved fusion and/or fixation device systemsand instrumentation are needed.

SUMMARY OF THE INVENTION

Aspects of the present invention provide fusion and/or fixation systemsand methods that can maintain or re-establish anatomic spacing within apatient's bones, for example, a patient's spine or bone fracturelocation.

In one aspect, provided here is a fusion system, including a first onepiece screw, a second one piece screw, and a rod coupled to the firstone piece screw at a first end and the second one piece screw at asecond end, wherein the rod may be positioned at varying angulationswith respect to the first and second one piece screws.

In another aspect, provided herein is a fusion system, including a firstfastener, a second fastener, and an elongate member with a first end anda second end, wherein the first end is secured to the first fastener andthe second end is secured to the second fastener.

In a further aspect, provided herein is a method for assembling a fusionsystem including: obtaining a first tower, a second tower, a firstfastener, a second fastener, and an elongate member; coupling the firstfastener to the first tower; coupling the second fastener to the secondtower; inserting a first end of the elongate member into the firstfastener; inserting a second end of the elongate member into the secondfastener; coupling a first locking cap to a screwdriver; screwing thefirst locking cap into a head of the first fastener to secure the firstend of the elongate member to the first fastener; coupling a secondlocking cap to a screwdriver; and screwing the second locking cap into ahead of the second fastener to secure the second end of the elongatemember to the second fastener.

In yet another aspect, provided herein is a surgical method forinserting a fusion system, including exposing a patient's vertebrae andobtaining the fusion system. The method may also include inserting afirst fastener into a first vertebra and inserting a second fastenerinto a second vertebra adjacent to the first vertebra. Further, themethod may include coupling the first fastener and second fastener.

These, and other objects, features and advantages of this invention willbecome apparent from the following detailed description of the variousaspects of the invention taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention andtogether with the detailed description herein, serve to explain theprinciples of the invention. The drawings are only for purposes ofillustrating preferred embodiments and are not to be construed aslimiting the invention. It is emphasized that, in accordance with thestandard practice in the industry, various features are not drawn toscale. In fact, the dimensions of the various features may bearbitrarily increased or reduced for clarity of discussion.

FIG. 1 is a perspective view of a bottom of a set screw and the base ofa fastener of a fusion system, in accordance with an aspect of thepresent invention;

FIG. 2 is a side view of a cross section of a set screw and the base ofa fastener of a fusion system, in accordance with an aspect of thepresent invention;

FIG. 3 is a perspective view of an elongate member for a fusion system,in accordance with an aspect of the present invention;

FIG. 4 is a partially exploded perspective view of a fusion system, inaccordance with an aspect of the present invention;

FIG. 5 is a partially exploded perspective view of another embodiment ofa fusion system, in accordance with an aspect of the present invention;

FIG. 6 is a cross-section of a fastener of the fusion system of FIG. 5taken along line 6-6, in accordance with an aspect of the presentinvention;

FIG. 7 is a perspective transparent view of an insertion tower, inaccordance with an aspect of the present invention;

FIG. 8 is a side transparent view of the insertion tower of FIG. 7, inaccordance with an aspect of the present invention;

FIG. 9 is a front perspective transparent view of the insertion tower ofFIG. 8, in accordance with an aspect of the present invention;

FIG. 10 is an exploded, perspective view of a screwdriver, in accordancewith an aspect of the present invention;

FIG. 11 is an assembled, perspective view of the screwdriver of FIG. 10,in accordance with an aspect of the present invention;

FIG. 12 is a side view of the screwdriver of FIG. 11, in accordance withan aspect of the present invention;

FIG. 13 is a first end view of the screwdriver of FIG. 12, in accordancewith an aspect of the present invention;

FIG. 14 is a partial, cross-sectional view of a fastener of the fusionsystem of FIG. 5 coupled to the insertion tower of FIG. 7, in accordancewith an aspect of the present invention;

FIG. 15 is a cross-sectional view of a portion of the assembled fusionsystem of FIG. 5, in accordance with an aspect of the present invention;

FIG. 16 is a top view of a fastener of the fusion system of FIG. 5, inaccordance with an aspect of the present invention;

FIG. 17 is a side cross-sectional view of a portion of fastener of thefusion system of FIG. 5 taken along line 17-17 in FIG. 16, in accordancewith an aspect of the present invention;

FIG. 18 is a side view the assembled fusion system of FIG. 5 in a firstposition, in accordance with an aspect of the present invention;

FIG. 19 is a top view of the assembled fusion system of FIG. 5 in asecond position, in accordance with an aspect of the present invention;

FIG. 20 is a side view of the assembled fusion system of FIG. 5 in athird position, in accordance with an aspect of the present invention;and

FIG. 21 is a side view of the fusion system of FIG. 5 in a fourthposition, in accordance with an aspect of the present invention.

DETAILED DESCRIPTION FOR CARRYING OUT THE INVENTION

Generally stated, disclosed herein are fusion and/or fixation systems.Further, methods of assembling the fusion and/or fixation systems andsurgical methods for inserting the fusion and/or fixation systems arediscussed.

In this detailed description and the following claims, the wordsproximal, distal, anterior, posterior, medial, lateral, superior,inferior, cephalad and caudally are defined by their standard usage forindicating a particular part of a bone or implant according to therelative disposition of the natural bone or directional terms ofreference. For example, “proximal” means the portion of an implantnearest the insertion instrument, while “distal” indicates the portionof the implant farthest from the insertion instrument. As fordirectional terms, “anterior” is a direction towards the front side ofthe body, “posterior” means a direction towards the back side of thebody, “medial” means towards the midline of the body, “lateral” is adirection towards the sides or away from the midline of the body,“superior” means a direction above and “inferior” means a directionbelow another object or structure, “cephalad” means a direction towardthe head and “caudally” means a direction toward the inferior part ofthe body.

Referring now to FIGS. 1, 2 and 5, a set screw 400 is shown. The setscrew or locking cap 400 may include a top surface 404 and a bottomsurface 406. The top surface 406 may include an opening 403 forreceiving a screwdriver. The bottom surface 406 may include a recess408. The recess 408 may include a radius R3, as shown in FIG. 15, anddescribed in greater detail below. The set screw 400 may also includethreads 410 on the exterior surface of the set screw 400 between the topsurface 404 and the bottom surface 406. For example, the set screw 400may be used with elongate members 550, 650 which each include ball ends552, 554, 652, 654 that would be received within the recess 408 on thebottom surface 406 of the set screws 400.

FIG. 3 shows an embodiment of an elongate member 290. The elongatemember 290 includes a first end 292 and a second end 294. The first end292 has a rectangular shape which angles at a tapered portion 296 to thesecond end 294 which is a ball end 298. The second end 294 may have adiameter larger than the diameter of the tapered portion 296 and thebody of the rod. The elongate member 290 may be used with, for example,a first fastener assembly 510 to receive the first end 292 and a secondfastener 530 to receive the second end 294 or vice versa, as describedin greater detail below.

As shown in FIG. 4, a fusion and/or fixation system 500 may include afirst fastener 510, a second fastener 530, and an elongated member 550.The first fastener 510 may include a shaft 512, a head 514, and a neck516 connecting the shaft 512 and head 514. The shaft 512 may bethreaded, for example, along its entire length or along only a portionof the length or alternatively, the shaft 512 may be non-threaded. Thehead 514 may include a first arm 518, a second arm 520, and a passageway522 extending between the first arm 518 and the second arm 520. Thefirst arm 518 and second arm 520 each have an interior surface formed bythe passageway 522. The passageway 522 creates two openings separatingthe first arm 518 and the second arm 520. The openings of the passageway522 are sized to allow a center portion 556 of the elongate member 550or the first end 292 of the elongate member 290 to pass through theopenings, but not the ball ends 294, 552, 554 of the elongate members290, 550, respectively. The passageway 522 also forms a base 524 nearthe bottom of the head 514. The base 524 may be, for example, planar asillustrated, alternatively, the base 524 may be curved or arced tocorrespond to the shape of the first end 552 of the rod 550. Forexample, the base 524 may be concave. The first arm 518 and the secondarm 520 may each be curved to form a rounded passageway 522 forreceiving the rod 550. In addition, the first arm 518 and the second arm520 may have, for example, a threaded portion 526 that extends along atleast a portion of the interior surface of each of the first and secondarms 518, 520 from a top surface of the head 514 toward the base 524.The threaded portion 526 may receive a locking mechanism (not shown),such as, set screw 400, to secure the elongate member 550 to the firstfastener 510. The locking mechanism (not shown) may have a bottomsurface that is dimensioned to couple to the rounded end 552 of theelongate member 550. Thus, the bottom surface of the locking mechanismmay be, for example, concave. Alternatively, the locking mechanism maybe, for example, a press fit mechanism to secure the elongate member 550to the heads 514, 534 of the fasteners 510, 530.

With continued reference to FIG. 4, the second fastener 530 may includea shaft 532, a head 534, and a neck 536 connecting the shaft 532 andhead 534. The shaft 532 may be threaded, for example, along its entirelength or along only a portion of the length, or alternatively, theshaft 532 may be non-threaded. The head 534 may include a first arm 538,a second arm 540, and a passageway 542 extending between the first arm538 and the second arm 540. The first arm 538 and the second arm 540each have an interior surface formed by the passageway 542. Thepassageway 542 also forms a base 544 near the bottom of the head 534.The base 544 may be, for example, planar as illustrated, alternatively,the base 544 may be curved or arced to correspond to the rounded shapeof the rod 550. The first arm 538 and the second arm 540 may each becurved to form a rounded passageway 542 for receiving the rod 550. Inaddition, the first arm 538 and the second arm 540 may have, forexample, a threaded portion 546 that extends along at least a portion ofthe interior surface of each of the first and second arms 538, 540 froma top surface of the head 534 toward the base 544. The threaded portion546 may receive a locking mechanism (not shown) to secure the elongatemember 550 to the second fastener 530, for example, set screw 400. Thelocking mechanism (not shown) may have a bottom surface that isdimensioned to couple to the rounded end 554 of the elongate member 550.Thus, the bottom surface of the locking mechanism may be, for example,concave.

The elongate member 550, as shown in FIG. 4, may include a first end552, a second end 554, and a center portion 556 extending between thefirst end 552 and second end 554. The first end 552 and second end 554may be rounded to correspond to the rounded passageways 522, 542 of thefirst and second fasteners 510, 530, respectively. The center portion556 may be, for example, smaller than the first end 552 and the secondend 554. For example, the center portion 556 may have a width that issmaller than the diameter of the first and second ends 552, 554. Theelongate member 550 may also include a first tapered portion 558coupling the center portion 556 to the first end 552 and a secondtapered portion 560 coupling the center portion 556 to the second end554. The first tapered portion 558 and the second tapered portion 560may have a smaller dimension than the first end 552 and second end 554,respectively.

Another fusion and/or fixation system 600 is shown in FIG. 5 and mayinclude a first fastener 610, a second fastener 630, an elongated member650, and two locking members or caps 400. As shown in FIGS. 5-6 thefirst fastener 610 may include a shaft 612, a head 614, and a neck 616connecting the shaft 612 and head 614. The shaft 612 may be threaded,for example, along its entire length or along only a portion of thelength, alternatively, the shaft 612 may also be non-threaded. Asdepicted in FIGS. 5 and 6, the shaft 612 may include varying threadconfigurations along the shaft 612 length, for example, the shaft 612may include a single lead thread 611 at the distal end of the shaft 612and a dual lead thread 613 at the proximal end of the shaft 612. Thedual lead thread 613 provides increased bone contact within the corticalmargin to increase fastener 610 stability. The dual lead thread 613 mayextend into the tapered neck 616 of the fastener 610 to provideadditional cortical bone purchase and allow for potential bone ingrowthinto the thread form for increased fixation. The shaft 612 may alsoinclude a leading tip 615. The leading tip 615 may include, for example,a sharp cutting edge to assist with inserting the fastener 610 into thebone, which may eliminate the need for tapping into the bone prior toimplantation of the fastener 610.

With continued reference to FIGS. 5 and 6, the head 614 may include abody 618 with an opening or slot 620 extending into the body 618 fromthe top of the head 614 and a portion of the body 618. The body 618 maybe curved and may extend, for example, circumferentially greater than180° and less than 345° leaving an opening 620 of, for example, greaterthan 15° and less than 180°, and more preferably may be curved and mayextend, for example, circumferentially approximately 270° leaving anopening 620 of, for example, approximately 90°. The opening 620 mayextend from the top surface of the head 614 down to a position below themidline of the head 620. The body 618 only, including one opening 620provides additional support for the rod 650 to prevent longitudinalmovement of the rod 650 after insertion into the patient. The opening620 is shaped to provide for rod translation in both the axial plane,i.e. up and down direction, and the rotational plane, i.e. left andright direction. The opening 620 may also be shaped to allow forrotation of the head 614 of the fastener 610 about the multi-axis of thefirst end 652 or the rod 650. In one embodiment, as shown in FIGS. 16and 17, the opening 620 allows for, for example, an angle γ of rodpositioning in the axial plane and an included angle α, β of rodpositioning in the rotational plane. For example, γ may range fromapproximately 5° to 75° and more preferably from approximately 20° to40°, α may range from approximately 1° to 70° and more preferably fromapproximately 5° to 15°, and β may range from approximately 1° to 70°and more preferably from approximately 5° to 15°. In one embodiment, forexample, γ may be approximately 34°, α may be approximately 10°, and βmay be approximately 10°. The opening 620 allows for rod angulationand/or positioning that provides for anatomic variability of the rod 650when inserted into the fastener 610, while capturing the ball end 652 tomaintain the distance between the first fastener 610 and the secondfastener 630. The anatomic variability enables the rod 650 to beimplanted into a patient at an angle when desirable for correction. Thethickness of the rod 650 may also be altered to provide for a larger orsmaller angle for the desired correction. The body 618 may have aninterior surface formed by the opening 620.

The opening 620 also forms a base 622 near the bottom of the head 614,as shown in FIGS. 5 and 6. The base 622 may be, for example, curved orarced to match the shape of the first end 652 of the rod 650 asillustrated, alternatively the base 622 may be planar. The body 618 maybe curved to receive the rounded end of the rod 650. In addition, thebody 618 may have, for example, a threaded portion 624 that extendsalong at least a portion of the interior surface of the body 618 from atop surface of the head 614 towards the base 622. The threaded portion624 may receive a locking mechanism to secure the elongate member 650 tothe first fastener 610, such as, set screw or locking cap 400. Thelocking mechanism 400 may have a recess 408 that is shaped to receivethe rounded end 652 of the elongate member 650. For example, the recess408 of the set screw 400 may be dimensioned to be smaller than the firstend 652 of the elongate member 650. Thus, the bottom surface of thelocking mechanism may be, for example, concave. The head 614 may alsoinclude a ridge 670 extending around the exterior surface of the head614. The head 614 may further include a first tab 672 and a second tab674 on the exterior surface of the head 614 and positioned between thetop of the fastener 610 and the ridge 670.

As shown in FIG. 5, the second fastener 630 may be of the type describedabove with reference to first fastener 610. The second fastener 630 mayinclude a shaft 632, a head 634 with a body 638, an opening 640, a base(not shown) and a threaded portion 644, and a neck 636 extending betweenthe head 634 and shaft 632, which may be of the type described abovewith reference to the shaft 612, head 614 with the body 618, an opening620, a base 622 and a threaded portion 624, and a neck 616 which willnot be described again here for brevity sake. A locking mechanism, suchas, set screw 400, may also be used with the second fastener 630 forinsertion into the head 634 to engage the threaded portion 644. Thelocking mechanism 400 may be used to secure the elongate member 650 tothe second fastener 630. The locking mechanism 400 may include a recess408 that is shaped to correspond to the rounded end 654 of the elongatemember 650. The recess 408 in the locking mechanism 400 may have acurvature dimensioned to be smaller than the curvature of the roundedend 654 to secure the rounded end 654 in the head 634 of the fastener630. Alternatively, the locking mechanism may be, for example, a pressfit mechanism to secure the elongate member 650 to the heads 614, 634 ofthe fasteners 610, 630. Once both locking mechanisms 400 are secured inthe fasteners 610, 630, the distance between the fasteners 610, 630 issecured.

The elongate member or rod 650, as shown in FIG. 5, may include a firstend 652, a second end 654, and a shaft portion 656 extending between thefirst end 652 and second end 654. The first end 652 and second end 654may be rounded or ball ends with shapes to correspond to the roundedopenings 620, 640 of the first and second fasteners 610, 630,respectively. The ball ends 652, 654 may be sized such that they have adiameter larger than the diameter of the shaft portion 656, as well as,the recess 408 of the set screw 400 and the base 622 of the fasteners610, 630, as shown in FIG. 15. The ball ends 652, 654 may have, forexample, highly roughened or textured surfaces. The textured surfaces ofthe ball ends 652, 654 may assist with securing the elongate member 650between the fasteners 610, 630 and the set screws 400. The roughened ortextured surface may be of the type to allow for deformation of theroughened or textured surface when the set screw 400 is tightened intothe head 614, 634 of the fastener 610, 630. The elongate member 650 mayalso include a first connection portion 658 coupling the center portion656 to the first end 652 and a second connection portion 660 couplingthe center portion 656 to the second end 654.

The fasteners 510, 530, 610, and 630 may be cannulated through thecenter of the shaft along a longitudinal axis of the fasteners 510, 530,610, and 630 and include an opening, for example, opening 626 offastener 610, as shown in FIG. 6, to enable insertion over a guide wire,k-wire, pin, or the like to assist with insertion into the patient. Asshown in FIG. 6, the base 622 of the fastener 610 may include a screwengagement portion 628 positioned at the top of the opening 626. Thescrew engagement portion 628 may be shaped to correspond to thescrewdriver instrument, such as screwdriver 800 described in greaterdetail below, for insertion of the fasteners 510, 530, 610, 630. Thescrew engagement portion 628 may have, for example, a femalecylindrical, hexagon, or other polygonal shape.

A system for inserting the device 600 may include an insertion tower ortube 700, as shown in FIGS. 7-9, a screwdriver 800, as shown in FIGS.10-13, and two fastener systems 610, 630. The insertion tower 700 mayhave a body 702 with a first end 704 and a second end 706. The body 702may have a central opening 708 through the center of the body 702 alongthe longitudinal axis. The body 702 may also include a cutout 710 at thefirst end 704 of the body 702 extending from an exterior surface to aninterior surface of the body 702. The body 702 may further include achannel 712 extending from the second end 706 of the body 702 toward thefirst end 704 and an opening 714 positioned opposite the channel 712.The channel 712 and opening 714 each extend from the exterior surface tothe interior surface of body 702 allowing for insertion of a rod 290,550, 650. The body 702 may also include a first slot 716 extending fromthe second end 706 of the body 702 to an opening 718 which may be, forexample, a round opening, and a second slot 720 extending from a secondend 706 of the body 702 to an opening 722 which may be, for example, around opening. The slots 716, 720 may be positioned between the channel712 and the opening 714 at the second end 706 of the body 702. Althoughonly two slots 716, 720 are shown, it is also contemplated thatadditional slots may be included in the tube 700 to allow for expansionof the tube 700 when a fastener 610, 630 is inserted or removed from thetube 700. The interior side of the body 702 may include a groove 724positioned at the second end 706. The groove 724 may be sized to receivethe ridge 670 on the exterior surface of the fasteners 610, 630.

Referring now to FIG. 14, a cross-section of the fastener 610 is showninserted into an insertion tube 700. To insert the fastener 610 into thetube 700, the first tab 672 may be aligned with the second slot 720 andthe second tab 674 may be aligned with the first slot 716. In addition,the opening 620, 640 of the fastener 610, 630 may be aligned with thechannel 712 of the tower 700. As the tabs 672, 674 are inserted into theslots 716, 720, the tube 700 will expand to allow the head 614 to beinserted into the central opening 708. The head 614 may be inserted intothe central opening 708 until the ridge 670 of the head engages thegroove 724 to secure the fastener 610 to the tube 700. To enable thefastener 610 to be secured to the tube 700, the inner diameter of thetube 700 may be, for example, the same dimension as the outer diameterof the head 614 of the fastener 610.

FIGS. 10-13 show the screwdriver 800 which is shaped to engage thefasteners 610, 630 for insertion into a patient. In addition, thescrewdriver 800 is sized to be used with the tube 700 and able to beinserted through the central opening 708 of the tube 700. Thescrewdriver 800 may include a handle portion 810 at a first end 802 ofthe screwdriver 800 and a shaft portion 820 extending from the handleportion 810 to the second end 804. The handle portion 810 may bepositioned generally perpendicular to the shaft portion 820. The handleportion 810 may include a body 812 and an opening 814 for receiving oneend of the shaft portion 820. The shaft portion 820 may include a shaft822 with a screw member 824 at the second end 804 of the screwdriver800. The screw member 824 may be sized for engaging the opening 628, asshown in FIGS. 6 and 14, of fasteners 610, 630. In addition, the screwmember 824 may be sized and shaped to also engage an opening 403 in theset screw 400 to securely tighten the set screw 400 against the rod 650.The screw member 824 may have, for example, a torque, hexagon or anyother polygonal shape. The second end 804 of the screwdriver 800 mayalso include a tab or protrusion 826 for engaging the opening 620 in thefastener 610 to drive the fasteners 610, 630 into a patient's bone. Thescrewdriver 800 may further include a cannulated opening 828 forreceiving a guide wire. The cannulated opening 828 may extend along theshaft 822 to a slot (not shown) in the handle portion 810 which allowsthe guide wire to be turned into the body 812 of the handle portion 810to avoid piercing the surgeons gloves.

Referring now to FIG. 15, a portion of the fusion system 600 includingthe fastener 610, rod 650, and locking cap 400 are shown as partiallyassembled. To reduce and/or eliminate the incident of axial androtational motion the radii of the fastener 610, rod 650, and lockingcap 400 have been selected to provide a locking fit between the fastener610, rod 650, and locking cap 400. The rounded end 652 of the rod 650has a curvature indicated by R1. The base 622 of the head 614 offastener 610 has a curvature indicated by R2. The recess 408 of thelocking cap 400 has a curvature indicated by R3. In one embodiment, forexample, the curvature of R1 will be greater than or equal to thecurvature of R2 to form an interference fit between the fastener 610 andthe rod 650 once secured with the locking cap 400. As described ingreater detail above, the ball ends 652, 654 of the rod 650 may have asurface finish that is, for example, rough, nearly knurled, or smooth,to allow for the surface of the ball ends 652, 654 to deform andsecurely retain the rod 650 within the head 614 of the fastener 610.Further, the curvature R3 of the locking cap 400 may be less than orequal to the curvature of R1 of the rod 650. Where R3 is less than orequal to R1, the locking cap 400 will make contact with the rod 650 nearthe point where the bottom surface 406 meets the recess 408 and the rod650 will not make contact with the apex of the recess 408. Therefore,when R3 is less than or equal to R1, there will be a non-contact areagap between the ball end 652 of the rod 650 and the recess 408 of thelocking cap 400 to reduce or eliminate the rod 650 from slipping.

Referring now to FIGS. 18-21, the rod 650 is shown inserted intofasteners 610, 630. In FIG. 18, the rod 650 is positioned angled betweenthe first fastener 610 and the second fastener 630 inserted at varyingheights. The second fastener 630 may be positioned, for example, at agreater height than the first fastener 610. Further, FIG. 19 shows therod 650 positioned angled with respect to the first and second fasteners610, 630 with the first fastener 610 offset from the second fastener630. The rod 650 may be positioned angled between the first fastener 610and second fastener 630 and may be positioned with the first fastener610 located, for example, at a height greater than the second fastener630, as shown in FIG. 20. In addition, FIG. 21 shows the first andsecond fasteners 610, 630 rotated about the long axis of the rod 650 andoffset from each other. Once the rod 650 is inserted into the fasteners610, 630, the load is in compression, tension, or neutral. The load onthe rod 650 is perpendicular to the axis of the fasteners 610, 630. Asillustrated by FIGS. 18-21, the fasteners 610, 630 are configured toaccommodate multi-axial positioning with respect to the rod 650.

A first method for inserting the devices 500, 600 of FIGS. 4-5 into apatient may include cutting a small incision in the patient, forexample, a 3 cm incision. Next the fascia is cut and muscles are splitin line of the fibers to expose the patient's vertebrae. Once thevertebrae are exposed, an image guidance or fluoroscopy device may beused to insert a first fastener or pedicle screw 510, 610 into a firstpedicle of a first vertebra and a second fastener or pedicle screw 530,630 into an adjacent second pedicle of a second vertebra. The fasteners510, 610, 530, 630 may be inserted using a guide wire if the fasteners510, 610, 530, 630 are cannulated or free hand. Then the elongatemembers 550, 650 may be lowered into the heads 514, 614, 534, 634 of thefasteners 510, 610, 530, 630, respectively. An elongate member 550, 650that is shorter than the in situ distance between heads 514, 614 andheads 534, 634 may be used for compression of the engaged vertebrae.While an elongate member 550, 650 that is longer than the in situdistance between the heads 514, 614 and heads 534, 634 may be used fordistraction of the engaged vertebrae. As the ball ends of the elongatemember 550, 650 are inserted into the heads 514, 534, 614, 634 thegeometry of the ball ends align with the feature of the fasteners toeither compress or distract the construct. As the ball ends are insertedinto the heads 514, 534, 614, 634, the elongate member 550, 650completes the compression or distraction of the bones. A lockingmechanism, for example, set screws or locking cap 400 may be insertedinto the heads 514, 614, 534, 634 of the first and second fasteners 510,610, 530, 630 and tightened down to secure the elongate members 550, 650to the fasteners 510, 610, 530, 630.

Alternatively, the second fastener 530, 630 may be secured to the secondend 554, 654 of the elongate member 550, 650 prior to insertion of thesecond fastener 530, 630 into the second pedicle. Then after insertionof the coupled second fastener 530, 630 and elongate member 550, 650,the elongate member 550, 650 may be lowered into the head 514, 614 ofthe first fastener 510, 610. The first end 552, 652 of the elongatemember 550, 650 is then secured to the first fastener 510, 610.Optionally, additional intermediate fixation devices may be used betweenthe end point fasteners 510, 530, 610, 630. Finally, the patient'sincision may be closed.

Another method for inserting the devices 600 of FIG. 5 into a patientmay include cutting a small incision in the patient. Next the fascia iscut and muscles are split in line of the fibers to expose the patient'svertebrae, which may be done using dilators. Once the vertebrae areexposed, an insertion system including a tower 700, a fastener 610, 630and a screwdriver 800 may be assembled for insertion of each of thefasteners 610, 630 into the patient's bone, as described in greaterdetail above. An image guidance or fluoroscopy device may be used toconfirm proper positioning of a first fastener or pedicle screw 610 intoa first pedicle of a first vertebra and a second fastener or pediclescrew 630 into an adjacent second pedicle of a second vertebra. Thefasteners 610, 630 may optionally be inserted using a guide wire sincethe fasteners 610, 630 are cannulated or free hand. Once the fasteners610, 630 are inserted into the vertebrae, the elongate member 650 may beinserted into the heads 614, 634 of the fasteners 610, 630,respectively. An elongate member 650 that is shorter than the in situdistance between head 614 and head 634 may be used for compression ofthe engaged vertebrae. While an elongate member 650 that is longer thanthe in situ distance between the head 614 and head 634 may be used fordistraction of the engaged vertebrae. As the elongate member 550, 650 isinserted into the heads 514, 534, 614, 634 the force of inserting theelongate member 550, 650 completes the correction of the bones. Alocking mechanism, for example, set screws or locking caps 400 may beinserted into the heads 614, 634 of the first and second fasteners 610,630 and tightened down to secure the elongate member 650 to thefasteners 610, 630. Optionally, additional intermediate fixation devicesmay be used between the end point fasteners 610, 630. Finally, thepatient's incision may be closed.

The elongate members 290, 550, and 650 may have a length. The length ofthe elongate members 290, 550, and 650 will be selected based on theprocedure being performed and whether compression or distraction isdesired. For example, a rod that is longer than the position of the insitu fasteners will be used for distraction to move the engagedvertebrae apart and a rod that is shorter than the in situ position ofthe fasteners will be used for compression to pull the engaged vertebraetogether. The length of elongate members 290, 550, and 650 may rangefrom, for example, approximately 10 mm to 60 mm and more specificallyapproximately 20 mm to 50 mm. The elongate members 290, 550, and 650 maybe straight or curved along the longitudinal axis.

The above described methods may be used for surgical proceduresincluding, for example, lumbar, cervical, spinal trauma, pelvicfixation, fracture fixation, bone ends, and the like.

As may be recognized by those of ordinary skill in the art based on theteachings herein, numerous changes and modifications may be made to theabove-described and other embodiments of the present invention withoutdeparting from the scope of the invention. The fasteners, elongatemembers, and other components of the devices and/or systems as disclosedin the specification, including the accompanying abstract and drawings,may be replaced by alternative component(s) or feature(s), such as thosedisclosed in another embodiment, which serve the same, equivalent orsimilar purpose as known by those skilled in the art to achieve thesame, equivalent or similar results by such alternative component(s) orfeature(s) to provide a similar function for the intended purpose. Inaddition, the devices and systems may include more or fewer componentsor features than the embodiments as described and illustrated herein.For example, the components and features of FIGS. 1-6 may all be usedinterchangeably and in alternative combinations as would be modified oraltered by one of skill in the art. Accordingly, this detaileddescription of the currently-preferred embodiments is to be taken asillustrative, as opposed to limiting the invention.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprise” (andany form of comprise, such as “comprises” and “comprising”), “have” (andany form of have, such as “has”, and “having”), “include” (and any formof include, such as “includes” and “including”), and “contain” (and anyform of contain, such as “contains” and “containing”) are open-endedlinking verbs. As a result, a method or device that “comprises,” “has,”“includes,” or “contains” one or more steps or elements possesses thoseone or more steps or elements, but is not limited to possessing onlythose one or more steps or elements. Likewise, a step of a method or anelement of a device that “comprises,” “has,” “includes,” or “contains”one or more features possesses those one or more features, but is notlimited to possessing only those one or more features. Furthermore, adevice or structure that is configured in a certain way is configured inat least that way, but may also be configured in ways that are notlisted.

The invention has been described with reference to the preferredembodiments. It will be understood that the architectural andoperational embodiments described herein are exemplary of a plurality ofpossible arrangements to provide the same general features,characteristics, and general system operation. Modifications andalterations will occur to others upon a reading and understanding of thepreceding detailed description. It is intended that the invention beconstrued as including all such modifications and alterations.

Having thus described the preferred embodiments, the invention is nowclaimed to be:
 1. A fusion system, comprising: a first fastenercomprising a first head with a first slot, a first shaft and a firstneck coupling the first head to the first shaft, and wherein the firsthead comprises a body portion defining an interior surface and a topsurface, and a base portion extending below the body portion defining anconcave interior surface defined by a first radius, wherein the interiorsurfaces of the body portion and first base portion of the first headcooperatively forming a first cavity, and wherein the first slot extendsthrough the body portion from the top surface thereof and through aportion of the base portion to the first cavity; a first locking capcomprising a bottom surface with a concave first recess defined by asecond radius, the first locking cap threadably engaged with the bodyportion of the first head within the first cavity; a second fastenercomprising a second head with a second slot, a second shaft and a secondneck coupling the second head to the second shaft, and wherein thesecond head comprises a body portion defining an interior surface and atop surface, and a base portion extending below the body portiondefining a concave interior surface defined by a third radius, whereinthe interior surfaces of the body portion and the base portion of thesecond head cooperatively forming a second cavity, and wherein thesecond slot extends through the body from the top surface thereof andthrough a portion of the base portion to the second cavity; a secondlocking cap comprising a bottom surface with a concave second recessdefined by a fourth radius, the second locking cap threadably engagedwith the body portion of the second head within the second cavity; andan elongate member comprising a first spherical end, a second sphericalend, and a coupling shaft extending between the first and secondspherical ends, wherein the first spherical end of the elongate memberis secured to the first head of the first fastener within the firstcavity via the first locking cap, and the second spherical end of theelongate member is secured to the second head of the second fastenerwithin the second cavity via the second locking cap, wherein the firstspherical end is defined by a fifth radius and includes a diameter thatis larger than a diameter of the coupling shaft, and the secondspherical end is defined by a sixth radius and includes a diameter thatis larger than a diameter of the coupling shaft, wherein the diameter ofthe first spherical end is larger than a width of the first slot, andthe diameter of the second spherical end is larger than a width of thesecond slot, and wherein the fifth radius of the first spherical end islarger than the first radius of the first head and the second radius ofthe first locking cap, and wherein the sixth radius of the secondspherical end is larger than the third radius of the second head and thefourth radius of the second locking cap.
 2. The system of claim 1,wherein the first and second fasteners each define an axis, and whereinthe first slot extends from top surface of the first head of the firstfastener to a position below the mid-point of the first head of thefirst fastener along the axis thereof, and the second slot extends fromthe top surface of the second head of the second fastener to a positionbelow the mid-point of the second head of the second fastener along theaxis thereof.
 3. The system of claim 1, wherein the first locking capcomprises a driver opening on a top surface thereof, and the secondlocking cap comprises a driver opening on a top surface thereof.
 4. Thesystem of claim 1, wherein the first cavity of the first head comprisesan opening at the top surface thereof that is in communication with thefirst slot, and the second cavity of the second head comprises anopening at the top surface thereof that is in communication with thesecond slot.
 5. The system of claim 1, wherein each of the first headand the second head further comprise: a ridge extending around thecircumference of the exterior surface of the body portion; a first tabpositioned on the exterior surface of the body portion and extendingfrom the top surface thereof to the ridge; and a second tab positionedon the exterior surface of the body portion extending from the topsurface thereof to the ridge, the second tab being circumferentiallyspaced apart from the first tab.
 6. The system of claim 1, furthercomprising: an insertion tower for coupling to at least one of the firstfastener and the second fastener; and a screwdriver sized to engage atleast one of the first fastener and the second fastener.
 7. The systemof claim 6, wherein the insertion tower comprises: a body with a firstend and a second end; a central opening extending through the body alonga longitudinal axis from the first end to the second end; a channelextending from the second end toward the first end and through the bodyto the central opening; and at least one slot extending from the secondend toward the first end and positioned spaced apart from and parallelto the channel.
 8. The system of claim 7, wherein the at least one slotcomprises two slots spaced circumferentially around the body of theinsertion tower at the second end.
 9. The system of claim 8, wherein atleast one of the first head and the second head further comprise a ridgeextending around the circumference of the exterior surface of the bodyportion thereof, and wherein the insertion tower further comprises: agroove inset into the body of the insertion tower at the second end andsized to receive a ridge on the exterior surface of at least one of thefirst fastener and the second fastener.
 10. The system of claim 6,wherein the screwdriver comprises: a handle portion; and a shaft portioncoupled to a central part of the handle portion, wherein the handleportion is perpendicular to the shaft portion.
 11. The system of claim10, wherein the shaft portion of the screwdriver comprises: a shaft witha first end and a second end; a screw member positioned at the secondend for engaging at least one of the first fastener and the secondfastener; a protrusion for engaging a second opening of at least one ofthe first fastener and the second fastener.
 12. A method of assembling afusion system, comprising: obtaining a first tower, a second tower, andthe fusion system of claim 1; coupling the first fastener of the fusionsystem to the first tower; coupling the second fastener of the fusionsystem to the second tower; inserting the first spherical end of theelongate member into the first cavity of the first fastener; insertingthe second spherical end of the elongate member into the second cavityof the second fastener; engaging the first locking cap with ascrewdriver; screwing the first locking cap into the first cavity of thefirst head of the first fastener to secure the first spherical end ofthe elongate member to the first fastener; engaging the second lockingcap with a screwdriver; and screwing the second locking cap into thesecond cavity of the second head of the second fastener to secure thesecond spherical end of the elongate member to the second fastener. 13.The method of claim 12, further comprising: removing the first towerfrom the first fastener; and removing the second tower from the secondfastener.
 14. A surgical method for inserting a fusion system,comprising: exposing a patient's vertebrae; obtaining the fusion systemof claim 1; inserting the first fastener of the fusion system into afirst vertebra of the patient's vertebrae; inserting the second fastenerof the fusion system into a second vertebra adjacent to the firstvertebra of the patient's vertebrae; and coupling the first fastener andsecond fastener together via the elongate member of the fusion system.15. The method of claim 14, wherein the fusion system further comprises:at least one insertion tower for coupling to at least one of the firstfastener and the second fastener; and at least one screwdriver forcoupling to at least one of the first fastener, the second fastener, thefirst locking cap, and the second locking cap.
 16. The method of claim15, wherein at least one of the first head and the second head furthercomprise a ridge extending around the circumference of the exteriorsurface of the body portion thereof, and wherein the at least oneinsertion tower comprises: a body with a first end and a second end; acentral opening extending through the body along a longitudinal axisfrom the first end to the second end; a channel extending from thesecond end toward the first end and through the body to the centralopening; at least one slot extending from the second end toward thefirst end and positioned spaced apart from and parallel to the channel;and a groove inset into the body of the insertion tower at the secondend and sized to receive the ridge of at least one of the first fastenerand the second fastener; and wherein the at least one screwdrivercomprises: a handle portion; and a shaft portion coupled to a centralpart of the handle portion, wherein the handle portion is perpendicularto the shaft portion, the shaft portion comprising: a shaft with a firstend and a second end; a screw member positioned at the second end forengaging at least one of the first fastener and the second fastener; aprotrusion for engaging a second opening of at least one of the firstfastener and the second fastener.
 17. The method of claim 16, whereininserting the first fastener into the first vertebra comprises: couplingthe first fastener to the second end of the at least one insertion tube;inserting the screw member and the protrusion of the at least onescrewdriver into the first cavity of the first head of the firstfastener; and rotating the screwdriver to drive the first fastener intothe first vertebra.
 18. The method of claim 17, wherein inserting thesecond fastener into the second vertebra comprises: coupling the secondfastener to the second end of the at least one insertion tube; insertingthe screw member and the protrusion of the at least one screwdriver intothe second cavity of the second head of the second fastener; androtating the screwdriver to drive the second fastener into the secondvertebra.
 19. The method of claim 18, wherein coupling the firstfastener and the second fastener together via the elongate member of thefusion system comprises: inserting the first spherical end of theelongate member into the first cavity of the first head of the firstfastener; screwing the first locking cap into the first cavity of thefirst head of the first fastener to secure the first spherical end ofthe elongate member between the concave interior surface of the firsthead of the first fastener and the concave first recess of the bottomsurface of the first locking cap; inserting the second spherical end ofthe elongate member into the second cavity of the second head of thesecond fastener; and screwing the second locking cap into the secondcavity of the second head of the second fastener to secure the secondspherical end of the elongate member between the concave interiorsurface of the second head of the second fastener and the concave secondrecess of the bottom surface of the second locking cap.
 20. The methodof claim 19, wherein coupling the first fastener and the second fastenertogether via the elongate member may moves the first fastener and thesecond fastener with respect to each other, and wherein the movement ofthe first and second with respect to each other adds compression forces,maintains compression forces, adds distraction forces, or maintainsdistraction forces between the first and second vertebra.
 21. The systemof claim 1, wherein the first fastener is elongated along a first axisand the second fastener is elongated along a second axis, wherein afirst bottom end surface of the first slot defined by the base portionof the first head is positioned below the center of the first sphericalend of the elongate member along the first axis, and wherein a secondbottom end surface of the second slot defined by the base portion of thesecond head is positioned below the center of the second spherical endof the elongate member along the second axis.
 22. The system of claim21, wherein the first slot is configured to provide for angulation ofthe elongate member within the first cavity along a first axial planethat is aligned with the first axis between the first bottom end surfaceand the top surface of the first head with the range of 20 degrees to 40degrees, and wherein the second slot is configured to provide forangulation of the elongate member within the second cavity along asecond axial plane that is aligned with the second axis between thesecond bottom end surface and the top surface of the second head withthe range of 20 degrees to 40 degrees.
 23. The system of claim 22,wherein the first slot is configured to provide for angulation of theelongate member within the first cavity along a first rotational planethat is normal with respect to the first axis between opposing lateralsides of the first slot of the first head with the range of 10 degreesto 30 degrees, and wherein the second slot is configured to provide forangulation of the elongate member within the second cavity along asecond rotational plane that is normal with respect to the second axisbetween opposing lateral sides of the second slot of the second headwith the range of 10 degrees to 30 degrees.
 24. The system of claim 1,wherein the first fastener is elongated along a first axis and thesecond fastener is elongated along a second axis, and wherein the bodyportion of the first head is annular and extends continuouslycircumferentially about the first axis between opposing lateral sides ofthe first slot, and the body portion of the second head is annular andextends continuously circumferentially about the second axis betweenopposing lateral sides of the second slot.
 25. The system of claim 24,wherein the body portion of the first head extends circumferentiallyabout the first axis between opposing lateral sides of the first slotwithin the range of greater than 180 degrees and less than 345 degrees,and the body portion of the second head extends circumferentially aboutthe second axis between opposing lateral sides of the second slot withinthe range of greater than 180 degrees and less than 345 degrees.
 26. Afusion system, comprising: a rod comprising a first spherical end, asecond spherical end, and a shaft portion extending between the firstand second spherical ends; a first one piece screw that accommodatesmulti-axial positioning of the rod with respect to the first one piecescrew, comprising a first head with a first slot, a first shaft and afirst neck coupling the first head to the first shaft, wherein the firsthead comprises: a body portion defining an annular interior surface anda top surface; and a base portion extending below the body portiondefining an concave interior surface defined by a first radius, whereinthe interior surfaces of the body portion and first base portion of thefirst head cooperatively form a first cavity, and wherein the first slotextends through the body portion from the top surface thereof andthrough a portion of the base portion to the first cavity; a second onepiece screw that accommodates multi-axial positioning of the rod withrespect to the second one piece screw, comprising a second head with asecond slot, a second shaft and a second neck coupling the second headto the second shaft, wherein the second head comprises: a body portiondefining an annular interior surface and a top surface; and a baseportion extending below the body portion defining an concave interiorsurface defined by a third radius, wherein the interior surfaces of thebody portion and the base portion of the second head cooperatively forma second cavity, and wherein the second slot extends through the bodyfrom the top surface thereof and through a portion of the base portionto the second cavity; a first locking cap with a driver opening on a topsurface and a bottom surface with an concave first recess defined by asecond radius, the first locking cap threadably engaged with the bodyportion of the first head within the first cavity to couple the firstspherical end of the rod within the first cavity; and a second lockingcap with a driver opening on a top surface and a bottom surface with anconcave second recess defined by a fourth radius, the second locking capthreadably engaged with the body portion of the second head within thesecond cavity to couple the second spherical end of the rod within thesecond cavity, wherein the first spherical end is defined by a fifthradius and includes a diameter that is larger than a diameter of theshaft portion, and the second spherical end is defined by a sixth radiusand includes a diameter that is larger than a diameter of the shaftportion, wherein the diameter of the first spherical end is larger thana width of the first slot, and the diameter of the second spherical endis larger than a width of the second slot, wherein the fifth radius ofthe first spherical end is larger than the first radius of the firsthead and the second radius of the first locking cap, and wherein thesixth radius of the second spherical end is larger than the third radiusof the second head and the fourth radius of the second locking cap,wherein the first one piece screw is elongated along a first axis andthe second one piece screw is elongated along a second axis, wherein afirst bottom end surface of the first slot defined by the base portionof the first head is positioned below the center of the first sphericalend of the rod along the first axis, and wherein a second bottom endsurface of the second slot defined by the base portion of the secondhead is positioned below the center of the second spherical end of therod along the second axis.
 27. The system of claim 26, wherein the firstslot is configured to provide for angulation of the rod within the firstcavity along a first axial plane that is aligned with the first axisbetween the first bottom end surface and the top surface of the firsthead with the range of 20 degrees to 40 degrees, and wherein the secondslot is configured to provide for angulation of the rod within thesecond cavity along a second axial plane that is aligned with the secondaxis between the second bottom end surface and the top surface of thesecond head with the range of 20 degrees to 40 degrees.
 28. The systemof claim 27, wherein the first slot is configured to provide forangulation of the rod within the first cavity along a first rotationalplane that is normal with respect to the first axis between opposinglateral sides of the first slot of the first head with the range of 10degrees to 30 degrees, and wherein the second slot is configured toprovide for angulation of the rod within the second cavity along asecond rotational plane that is normal with respect to the second axisbetween opposing lateral sides of the second slot of the second headwith the range of 10 degrees to 30 degrees.